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ED-30-08-010-EN-C


Guidance on
information requirements
and chemical safety assessment
Volume 10: Exposure estimation and uncertainty
analysis
Contains Chapters R14, R15, R16, R17, R18 and
R19

May/July 2008



Guidance for the implementation of REACH



Guidance on information
requirements and chemical safety
assessment
Chapter R.14: Occupational Exposure
Estimation

May 2008



Guidance for the implementation of REACH

LEGAL NOTICE

This document contains guidance on REACH explaining the REACH obligations and how
to fulfil them. However, users are reminded that the text of the REACH regulation is the
only authentic legal reference and that the information in this document does not
constitute legal advice. The European Chemicals Agency does not accept any liability with
regard to the contents of this document.























© European Chemicals Agency, 2008
Reproduction is authorised provided the source is acknowledged.
2 CHAPTER R.14 – OCCUPATIONAL EXPOSURE ESTIMATION
PREFACE

This document describes the information requirements under REACH with regard to substance
properties, exposure, use and risk management measures, and the chemical safety assessment. It is
part of a series of guidance documents that are aimed to help all stakeholders with their preparation
for fulfilling their obligations under the REACH regulation. These documents cover detailed
guidance for a range of essential REACH processes as well as for some specific scientific and/or
technical methods that industry or authorities need to make use of under REACH.

The guidance documents were drafted and discussed within the REACH Implementation Projects
(RIPs) led by the European Commission services, involving stakeholders from Member States,
industry and non-governmental organisations. These guidance documents can be obtained via the
website of the European Chemicals Agency (http://echa.europa.eu/reach_en.asp). Further guidance
documents will be published on this website when they are finalised or updated.

This document relates to the REACH Regulation (EC) No 1907/2006 of the European Parliament
1and of the Council of 18 December 2006



1 Corrigendum to Regulation (EC) No 1907/2006 of the European Parliament and of the Council of 18 December 2006
concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), establishing a European
Chemicals Agency, amending Directive 1999/45/EC and repealing Council Regulation (EEC) No 793/93 and
Commission Regulation (EC) No 1488/94 as well as Council Directive 76/769/EEC and Commission Directives
91/155/EEC, 93/67/EEC, 93/105/EC and 2000/21/EC (OJ L 396, 30.12.2006); amended by Council Regulation (EC)
No 1354/2007 of 15 November 2007 adapting Regulation (EC) No 1907/2006 of the European Parliament and of the
Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) by reason of the
accession of Bulgaria and Romania (OJ L 304, 22.11.2007, p. 1).
3CHAPTER R.14 – OCCUPATIONAL EXPOSURE ESTIMATION

Convention for citing the REACH regulation
Where the REACH regulation is cited literally, this is indicated by text in italics between quotes.
Table of Terms and Abbreviations
See Chapter R.20

Pathfinder
The figure below indicates the location of Chapter R14 within the Guidance Document.


Information: available – required/needed
Exposure Assessment (EA)Hazard Assessment (HA)
R14
n Y
Dangerous Risk Characterisation (RC)Stop Or PBT?
y n IterationDocument in Risk
CSR controlled?
Communicate
ES via eSDS


4 4CHAPTER R.14 – OCCUPATIONAL EXPOSURE ESTIMATION

CONTENTS
R.14 OCCUPATIONAL EXPOSURE ASSESSMENT ............................................................ 7
R.14.1 Introduction..............................................................................................................................................................7
R.14.2 Types and routes of exposure ..................................................................................................................................7
R.14.3 Determinants of occupational exposure and RMMs................................................................................................9
R.14.4 Exposure estimation with measurements and modelling approaches....................................................................10
R.14.4.1 Introduction.......................................................................................................................................................10
R.14.4.2 Workplace exposure assessment rating criteria ................................................................................................12
R.14.4.3 Core information requirements .........................................................................................................................14
R.14.4.4 Use of measured data ........................................................................................................................................15
R.14.4.5 Selection of measured data ...............................................................................................................................17
R.14.4.6 Use of exposure estimation tools ......................................................................................................................22
R.14.4.7 ECETOC TRA tool...........................................................................................................................................22
R.14.4.8 Easy-to-use workplace control scheme for hazardous substances (EMKG/ BauA-COSHH)..........................37
R.14.5 Higher Tier exposure assessment ................................................................................................46
R.14.5.1 Stoffenmanager exposure model.....................47
R.14.5.2 RISKOFDERM dermal model..........................................................................................................................49
R.14.5.3 Advanced tool ...................................................................................................................................................52
R.14.6 REFERENCES .....................................................................................................................54

TABLES
Table R. 14-1 Workplace exposure assessment rating criteria .................................................................................................13
Table R. 14-2 Availability banding, dustiness and vapour pressure.........................................................................................25
Table R. 14-3 Workplace process categories used in ECETOC TRA......................................................................................26
Table R. 14-4 Process categories and dermal exposure in ECETOC TRA..............................................................................28
Table R. 14-5 Examples of EASE calculations (inhalation) for worker process categories ....................................................30
Table R.14-6 Examples of exposure categories and predicted EASE Dermal Exposures .......................................................32
Table R. 14-7 Modifiers for duration of activity ......................................................................................................................34
Table R. 14-8 Definition of dustiness bands....................................................................................39
Table R. 14-9 Definition of volatility bands.............................................................................................................................40
Table R. 14-10 Scale of use bands/one batch41
Table R. 14-11 Exposure potential bands (EP)*.......................................................................................................................42
Table R. 14-12 Control strategies .............................................................................................................................................42
Table R. 14-13 Predicted exposure ranges................................................................................................................................43
Table R. 14-14 Calculated evaporation times for T = 20°C (gloves) and T = 30°C (skin)......................................................57

5CHAPTER R.14 – OCCUPATIONAL EXPOSURE ESTIMATION

FIGURES
Figure R. 14-1 Relation between process temperature, boiling point and volatility ................................................................40
Figure R. 14-2 Overview of the Easy-to-use scheme as a Tier 1 tool ......................................................................................45

APPENDICES
Appendix R.14-1 Evaporation rate ...........................................................................................................................................56
Appendix R.14-2 Control guidance sheet numbering system and an example “weighing of solids” ......................................59
Appendix R.14-3 Example of exposure derivation with EMKG..............................................................................................63

6 6CHAPTER R.14 – OCCUPATIONAL EXPOSURE ESTIMATION
R.14 OCCUPATIONAL EXPOSURE ASSESSMENT
R.14.1 Introduction
This chapter provides support for estimating occupational exposures. It describes what information
is needed for the assessment at the different levels (Tiers) and how to deal with it. The first Tier
exposure estimations are meant to be conservative and may be well above the actual exposures. The
higher Tier exposure estimations are much more specific and require more detail for the estimation
parameters and exposure determinants. The higher Tier estimations require also much more
knowledge on the confidence that can be related to the estimation (see Chapter R.19).
Support is given to
• Collection of exposure information for establishing (the final) ESs
• Information needs for different Tiers
• Estimation or calculation of exposures
2For occupational exposure, the following stages of the life cycle of a substance are mainly relevant :
• Manufacturing: Chemical synthesis of the substance and its use as a chemical intermediate;
• Formulation: Mixing and blending into a preparation;
• Industrial use: Application of the substance, preparation/product in an industrial process;
• Professional use: Application of preparations/products in skill trade premises.
In the following sections an overview will be given of the elements that need to be focussed on in
an occupational exposure assessment as it is required for REACH implementation. The following
elements need specific attention:
• Types of emission and sources (Section R.14.2)
• Determinants of occupational exposure (Section R.14.3)
• Exposure assessment with measurements and modelling approaches (Section R.14.4)
• Higher Tier exposure assessment (Section R.14.5)
• Current tool development (Section R.14.5)
R.14.2 Types and routes of exposure
Substances in the workplace may come into contact with the body and possibly enter the body by
inhalation, by contacting and passing through the skin (dermal), or sometimes even by swallowing
(ingestion). Exposure to a particular substance should normally be understood as external exposure.
This can be defined as the amount of the substance ingested, the amount in contact with the skin
and/or the amount inhaled, which is represented by the airborne concentration of the substance in
the breathing zone of a worker. It does not usually refer to concentrations within the body, which
are consistent with some measure of absorbed dose. Text on the exposure should therefore clearly
indicate whether the exposures under discussion are external or internal.
Exposure can be considered as a single event or as a series of repeated events or as continuous
exposure. As well as an estimation of the levels of exposure, either from measured or modelled
data, the scenario needs to address also other parameters such as duration and frequency of
exposure. It appears appropriate on the basis of current thinking to consider task-based exposures,

2 Other life stages may be relevant as well (e.g. the waste stage) and should be assessed when relevant
7CHAPTER R.14 – OCCUPATIONAL EXPOSURE ESTIMATION
also for acute effects. Exposure to substances causing local effects may also be of interest and
should be described where appropriate.
Inhalation
Exposure by inhalation is expressed as the concentration of the substance in the breathing zone
atmosphere and is normally presented as an average concentration over a reference period. For
comparison with hazards after repeated or continuous exposure a reference period of a full shift
(nominally 8 hours) is generally used. If the substance of concern has acute health effects or if
exposure is of intermittent short duration there may also be interest in exposure over shorter
periods. The assessment can also be based on exposure during specific tasks which may be carried
out over varying time periods. Inhalation exposure may occur due to gases and vapours, as well as
aerosols (liquid and solid) which may be available in the ambient air. Especially exposure to
aerosols is difficult to assess properly, since the particle size may vary with time and place and
particle size determines the degree of uptake in the body by inhalation (through the lungs) and by
ingestion (through the oral route). In some first Tier models, dustiness is used as a surrogate for
solid aerosol exposure.
Inhalation exposure can be influenced by the concentration of the substance, and the duration and
frequency of exposure. Inhalation exposure is generally expressed in ppm or amount per air volume
inhaled, averaged over the relevant task or shift.
Dermal exposure
For many substances the main route of exposure is by inhalation; however, substances may also
have local effects on the skin or may have the ability to penetrate (even intact) skin and become
absorbed into the body. Two terms can be used to describe dermal exposure:
• potential dermal exposure is an estimate of the amount of contaminant landing on the outside of
work wear and on the exposed surfaces of the skin. It is the sum of the exposure estimates for
the various body parts, including hands and feet;
• actual dermal exposure is an estimate of the amount of contamination actually reaching the
skin. It is mediated by the efficiency and effectiveness of clothing assemblages and programmes
to minimise transfer of contamination from work wear to the skin.
Potential dermal exposure is the most frequently used indicator.
Absorption through the skin can result from localised contamination, e.g. from a splash on the skin
or clothing or in some cases from exposure to high air concentrations of vapour. Dermal exposure
can be influenced by the amount and concentration of the substance, presence of highly permeable
other substances, the area of skin exposure and the duration and frequency of exposure.
8 8